Fixed-point formats provide representations of numbers having several digits. Decimal (or radix) points of the numbers are fixed at a specific position among the digits. For example, a seven-digit number with the decimal point positioned after the fifth digit can represent numbers such as 12345.67, 8765.43 and 123.00.
Floating-point formats provide representations of numbers having a several digits and decimal points that can be placed anywhere relative to the significant digits of the number. An advantage of the floating-point representations over the fixed-point representations is that the floating-point representations can support a wider range of values. For example, the digit sequence 1234567 can represent multiple floating-point numbers such as 1.234567, 123456.7, 0.00001234567 and 1234567000000000. However, the floating-point formats use slightly more storage than the fixed-point formats to encode the position of the decimal (radix) point.
It would be desirable to have a representation format available for numbers commonly experienced in image processing that uses less storage space than the floating-point formats and is not constrained to the positioning of the decimal point, as in the fixed-point representations.